Heretofore, various surfactants have been used as a foaming agent to enhance dispersibility of components blended and to improve a feeling upon use and a cleansing effect in an oral composition. For example, Patent Document 1 discloses a dentifrice composition in which an N-long-chain acyl glutamate is blended as the surfactant. In an oral composition described in Patent Document 2, there is made an attempt to further provide an effect of inhibiting the formation of stain by blending an amino acid-based surfactant. Further, an acylamino acid salt that is known as an amino acid-based surfactant having less skin and mucosal irritation may provide bitterness. Therefore, for example, Patent Document 3 discloses an oral composition that maintains good taste by blending an acylamino acid salt in as small an amount as 0.5 mass % or less and has a foaming ability enhanced by using a glucose fatty acid ester in addition to the acylamino acid salt.
On the other hand, it is known that blending of a pyrophosphate or the like can prevent the adhesion of dirt to a tooth surface. For example, Patent Document 4 discloses an oral composition including an alkyl sulfate, 1 wt % or more of a water-soluble polyphosphate such as a pyrophosphate and an orthophosphate. The document describes that the composition can enhance a chemical cleaning effect against dirt such as stain, plaque or tobacco tar on a tooth surface. Further, Patent Document 5 discloses a dentifrice composition in which an anionic surfactant, 0.3 to 1.5 mass % of a water-soluble pyrophosphate and specific hydroxypropyl cellulose are blended to exhibit an excellent tooth dirt-removing effect.